Predicting risk of pulmonary infection in patients with primary membranous nephropathy on immunosuppressive therapy: The AIM‐7C score

Development and validation of a nomogram for predicting pulmonary infection in patients receiving immunosuppressive drugs

Objective: Pulmonary infection (PI), a severe complication of immunosuppressive therapy, affects patients' prognosis. As part of this study, we aimed to construct a pulmonary infection prediction (PIP) model and validate it in patients receiving immunosuppressive drugs (ISDs). Methods: Totally, 7,977 patients being treated with ISDs were randomised 7:3 to the developing (n = 5,583) versus validation datasets (n = 2,394). Our predictive nomogram was established using the least absolute shrinkage and selection operator (LASSO) and multivariate COX regression analyses. With the use of the concordance index (C-index) and calibration curve, the prediction performance of the final model was evaluated. Results: Among the patients taking immunosuppressive medication, PI was observed in 548 (6.9%). The median time of PI occurrence after immunosuppressive therapy was 123.0 (interquartile range: 63.0, 436.0) days. Thirteen statistically significant independent predictors (sex, age, hypertension, DM, malignant tumour, use of biologics, use of CNIs, use of methylprednisolone at 500 mg, use of methylprednisolone at 40 mg, use of methylprednisolone at 40 mg total dose, use of oral glucocorticoids, albumin level, and haemoglobin level) were screened using the LASSO algorithm and multivariate COX regression analysis. The PIP model built on these features performed reasonably well, with the developing C-index of 0.87 (sensitivity: 85.4%; specificity: 81.0%) and validation C-indices of 0.837, 0.829, 0.832 and 0.830 for predicting 90-, 180-, 270- and 360-day PI probability, respectively. The decision curve analysis (DCA) and calibration curves displayed excellent clinical utility and calibration performance of the nomogram. Conclusion: The PIP model presented herein could aid in the prediction of PI risk in individual patients who receive immunosuppressive treatment and help personalise clinical decision-making.

Efficacy and safety of rituximab in elderly patients with membranous nephropathy

Objectives: Advancing age is a risk factor for treatment-related side effects and mortality in membranous nephropathy (MN) patients treated with traditional immunosuppressive regimens. This study aimed to determine the efficacy and safety of rituximab (RTX) in the treatment of elderly patients with MN. Methods: We performed a single center retrospective review of 37 consecutive MN patients aged 70 and older at the time of RTX infusion. We also enrolled 76 young patients (<70 years old) with MN as the control group. We assessed clinical and laboratory indices, remission rates, and adverse events at RTX infusion, 3 months, and last visit. Results: A total of 37 elderly patients with MN were included, with a median follow-up period of 15.50 (10.00, 24.40) months. Of the 37 patients, 75.68% were male, and mean age was 71.89 ± 2.47 years. At last visit, 7 (18.92%) patients achieved complete remission, and 26 (70.27%) patients achieved complete or partial remission. There were no differences in the complete remission rate and complete or partial remission rate at last visit compared to young patients (26.32% vs. 18.92%, p = 0.387; 85.53% vs. 70.27%, p = 0.055). After RTX treatment, three of 6 elderly patients with pneumonia died due to ineffective treatment of the infection in RTX therapy courses. The results of multivariant regression analysis showed that elderly patients have an increased risk of serious infection, compared with patients younger than 70 years (OR = 32.874, 95% CI 1.300-831.490, p = 0.034). For each increase of 1 g/L in serum albumin, the risk of serious infection would decrease by 43.2% (OR = 0.568, 95% CI 0.334-0.969, p = 0.038). Conclusion: This study demonstrates that RTX is effective in the treatment of elderly patients with MN. However, we also observed a high incidence of infectious complications. Our experience was limited by its retrospective design and relatively small sample size, and further randomized controlled studies with large sample size are needed to confirm our preliminary findings.

Pulmonary cryptococcosis closely mimicking lung cancer in a membranous nephropathy patient taking calcineurin inhibitor

In patients with membranous nephropathy (MN), malignancy may be either the underlying disease or results of immunosuppressive therapy which may also lead to opportunistic infections including the pulmonary cryptococcosis. On CT scan, nodule is the most common feature in pulmonary cryptococcosis and it can mimic lung cancer both clinically and radiologically. Therefore, pulmonary nodular lesions caused by cryptococcosis may be easily misdiagnosed and require unnecessary surgical treatment. As such, we herein presented an isolated subpleural solitary nodule with satellite lesion that closely mimicked lung cancer on both contrast-enhanced computed tomography (CT) scan and 18F-fluorodeoxyglucose positron emission tomography (FDG-PET)/CT in an MN patient under long-term tacrolimus regimen. Cryptococcosis was ascertained by the finding of oval thick-walled yeast on histopathology of the lung biopsy specimen taken during the Argon-Helium cryotherapy. Further, the pulmonary lesions progressively dissipated after antifungal treatment. Arguably, our experience may help clinicians in general and nephrologists in particular with a better understanding of the cryptococcal infection manifesting as pulmonary nodule(s) in the MN patients and contribute to more efficacious differential diagnosis against the lung cancer.

Clinical characteristics and risk factor analysis of Pneumocystis jirovecii pneumonia in patients with CKD: a machine learning-based approach

Patients with chronic kidney disease (CKD) who are being treated with immunosuppressive medications are at risk for developing Pneumocystis jirovecii pneumonia (PCP). We attempted to characterize the clinical aspects of PCP in CKD patients in order to alert high-risk patients with bad prognosis. A retrospective study of CKD patients was conducted from June 2018 to June 2022. Based on PCP diagnostic criteria, these patients were divided into PCP and non-PCP groups. Using univariate and multivariate logistic regression analysis, risk indicators were evaluated, and nomogram and decision tree were developed. Of the CKD patients screened for Pneumocystis carinii nucleic acid, 1512 were included. Two-hundred forty four (16.14%) were diagnosed with PCP. Of the PCP, 88.5% was receiving glucocorticoid (GC) therapy, of which 66.3% received more than 0.5 mg/kg GC. Multivariate analysis showed that membranous nephropathy (OR 2.35, 95% CI 1.45-3.80), immunosuppressive therapy (OR 1.94, 95% CI 1.06-3.69), and ground glass opacity of CT scanning (OR 1.71, 95% CI 1.10-2.65) were associated with increased risk of Pneumocystis carinii infection. The AUC of nomogram based on logistics regression was 0.78 (0.75-0.81). The mortality in patients with PCP was 32.40%. Univariate analysis and decision tree showed that pulmonary insufficiency (PO₂: OR 0.98, 95% CI 0.96-1.00), elevated APTT (OR 1.07, 95% CI 1.04-1.11), and reduced hemoglobin (OR 0.97, 95% CI 0.96-0.98) were associated with poor prognosis. PCP is not rare in CKD patients, particularly in those treated with immunosuppressive therapy. Considering the high mortality of the cases, further studies on the prevention and management of these patients are needed.

Nocardia Infection in Nephrotic Syndrome Patients: Three Case Studies and A Systematic Literature Review

Objective

The multicenter literature review and case studies of 3 patients were undertaken to provide an updated understanding of nocardiosis, an opportunistic bacterial infection affecting immunosuppressed nephrotic syndrome (NS) patients receiving long-term glucocorticoid and immunosuppressant treatment. The results provided clinical and microbiological data to assist physicians in managing nocardiosis patients.

Methods

Three cases between 2017 and 2018 from a single center were reported. Additionally, a systematic review of multicenter cases described in the NCBI PubMed, Web of Science, and Embase in English between January 1, 2001 and May 10, 2021 was conducted.

Results

This study described three cases of Nocardia infection in NS patients. The systematic literature review identified 24 cases with sufficient individual patient data. A total of 27 cases extracted from the literature review showed that most patients were > 50 years of age and 70.4% were male. Furthermore, the glucocorticoid or corticosteroid mean dose was 30.9 ± 13.7 mg per day. The average time between hormone therapy and Nocardia infection was 8.5 ± 9.7 months. Pulmonary (85.2%) and skin (44.4%) infections were the most common manifestations in NS patients, with disseminated infections in 77.8% of patients. Nodule/masses and consolidations were the major radiological manifestations. Most patients showed elevated inflammatory biomarkers levels, including white blood cell counts, neutrophils percentage, and C-reactive protein. Twenty-five patients received trimethoprim-sulfamethoxazole monotherapy (18.5%) or trimethoprim-sulfamethoxazole-based multidrug therapy (74.1%), and the remaining two patients (7.4%) received biapenem monotherapy. All patients, except the two who were lost to follow-up, survived without relapse after antibiotic therapy.

Conclusions

Nephrotic syndrome patients are at high risk of Nocardia infection even if receiving low-dose glucocorticoid during the maintenance therapy. The most common manifestations of nocardiosis in NS patients include abnormal lungs revealing nodules and consolidations, skin and subcutaneous abscesses. The NS patients have a high rate of disseminated and cutaneous infections but a low mortality rate. Accurate and prompt microbiological diagnosis is critical for early treatment, besides the combination of appropriate antibiotic therapy and surgical drainage when needed for an improved prognosis.

Characteristics and risk factors for Pneumocystis jirovecii pneumonia in patients with idiopathic membranous nephropathy

Pneumocystis jirovecii pneumonia (PCP) is a life-threatening opportunistic infection in idiopathic membranous nephropathy (IMN) patients, who are treated with immunosuppressive drugs. However, the risk factors of infection and their prognosis are rarely investigated. We aimed to characterize the clinical manifestations of PCP in patients with IMN, and to understand their risk factors, so that we can provide early warnings to patients with high risk and potential poor prognosis. We conducted a retrospective observational study of IMN patients in a referral center in China, from Jan 2012 to Dec 2018. Clinical and laboratory data were collected separately at the time of IMN and PCP diagnosis. Patients with PCP were matched to those without by gender and age at a ratio of 1:4. The risk factors and prognostic factors were determined by univariate and multivariate logistic regression analysis. A total of 879 patients with IMN were included, with a median follow-up of 267 (interquartile range (IQR) 64,842) days. In total, 26 (2.96%) of them were diagnosed with PCP. The infection rate increased to 3.87% among patients who received corticosteroids, and it further increased to 5.49% in those received over 0.5mg/kg prednisone. Univariate analysis indicated that initial usage of corticosteroids, use of cyclophosphamide, reduced estimated glomerular filtration rate (eGFR), and higher 24-h proteinuria were related to the PCP susceptibility. Multivariate analysis revealed that corticosteroid treatment and reduced eGFR increased the risk of the Pneumocystis jirovecii infection. The case fatality rate of the PCP patients was 23.08%, and increased to 75% among patients requiring invasive ventilation. Univariate analysis indicated that pulmonary insufficiency, invasive ventilation, decreased eGFR, and increased lactate dehydrogenase at presentation were linked to poor prognosis. PCP is not rare in patients with IMN, especially those on corticosteroids, and presented with decreased eGFR. Considering the high case fatality rate, further studies are in need for prevention and management of these patients.

Membranous nephropathy with pulmonary cryptococcosis with improved 1-year follow-up results: A case report

Cryptococcosis is frequently found in immunosuppressed patients. It is also a significant opportunistic infection in non-immunocompromised individuals. In this study, we present a rare case of membranous nephropathy (MN) with pulmonary cryptococcosis. A 33-year-old man with MN was referred to our hospital because of dyspnea and weakness for 1 week. Before the above symptoms occurred, the dose of Cyclosporin A was increased again for relapse of MN. Multiple massive or patchy high-density shadows were present on computed tomography of the lung. Initially the patient underwent empirical anti-bacterial therapy, which turned out to be ineffective. As the results of serum cryptococcal latex agglutination tests were positive, the administration of anti-fungal drugs was prescribed. The results of fungal culture and pathologic examination of the lung tissue revealed the findings consistent with Cryptococcus neoformans. The patient was successfully treated with voriconazole followed by fluconazole with satisfactory result. Therefore, in patients with chronic kidney disease, lung lesions with poor bactericidal effects of cephalosporins need further examination to make sure whether there is pulmonary cryptococcosis. Early diagnosis and treatment might contribute to good results. It is a problem worthy of consideration that whether immunosuppressive agents need to be discontinued or not during antifungal therapy.

Disparate effects of methicillin-resistant Staphylococcus aureus infection on renal function in IgA-dominant infection-associated glomerulonephritis and menstrual toxic shock syndrome: a case report and literature review

The sudden outbreak of severe acute respiratory syndrome coronavirus 2 pneumonia posed a significant challenge to medical professionals because treatment of critically ill patients requires the efforts of a multidisciplinary team. To highlight this principle, we examined acute kidney injury (AKI) in IgA-dominant infection-associated glomerulonephritis (GN) and menstrual toxic shock syndrome (mTSS). Both GN and mTSS are rare diseases caused by staphylococcal infection, and renal function is frequently impaired. The resulting AKIs are disparate pathological entities driven by distinct immune mechanisms. We begin by describing the case of a diabetic man with pyopneumothorax following methicillin-resistant Staphylococcus aureus (MRSA). He had endocapillary proliferative GN with in situ IgA-dominant immune-complex formation in the mesangium accompanied by complement C3 deposition in the glomerular capillary wall. By contrast, acute tubular necrosis was observed in a case of mTSS; the patient’s immune response was stimulated differently by MRSA enterotoxin and exotoxin resulting in aberrant IgA deposition, complement activation, and insufficient antibody production. As a multidisciplinary communication covering the fields of nephrology, immunology, and pathology, this report may help clinicians to understand these distinct renal lesions and make optimal therapeutic decisions expeditiously.

The clinical characteristic and outcome of skin and soft tissue infection in immunosuppressive patients with nephrotic syndrome

OBJECTIVE

Skin and soft tissue infection (SSTI) is the most common of infectious diseases with high morbidity and mortality. However, the clinical characteristics of SSTI in patients with nephrotic syndrome (NS), especially in those patients who received immunosuppressive therapy, are still lacking. The present study was conducted to investigate the clinical characteristics and outcomes of SSTI in patients with NS.

METHODS

A retrospective study was carried out among the patients diagnosed with NS and SSTI, who have priorly received or currently have been receiving immunosuppressive therapy between April 2011 and January 2019; the clinical profile included patient's baseline characteristics, clinical presentation, microbiological findings, treatment, and prognosis.

RESULTS

A total of 70 patients were analyzed. Results showed that more than half of the patients were under 35 years old, and moderate infection was the most common type of SSTI. Leg and cellulitis were the most common site of lesion and the typical clinical manifestation of SSTI, respectively. Patients in the severe infection group have a higher level of procalcitonin (PCT) and C-reactive protein (CRP), while a lower level of albumin, CD4⁺ T and CD8⁺ T cell count. Moreover, the gram-negative bacteria were the primary pathogens of SSTI in patients with NS, and Klebsiella pneumoniae were the most frequent strains isolated from those patients. Besides, patients in the mild and moderate infection groups experienced a better outcome.

CONCLUSIONS

Patients with NS and SSTI usually showed a satisfying outcome with proper anti-infection treatment, but severe SSTI can be life-threatening.

From Severe Herpes Zoster to Rare Suid Herpesvirus Encephalitis: A New Twist of the Varicellovirus Genus Infection in Patients with Kidney Diseases

Both the herpes zoster virus and suid herpesvirus type 1 (SuHV-1) belong to the Varicellovirus genus of the α-herpesviridae subfamily. They may cause opportunistic infections especially in patients with kidney diseases, varying from latent illness to overt lethality. Under these circumstances, impaired renal function is both the culprit for and victim of the infection. However, fulminant eruption of severe skin herpes zoster in lupus nephritis (LN) patients under prolonged immunosuppressive therapy is rare and even more rarely seen is the SuHV-1 encephalitis in human. Facing the evolution of these rare infections, we hence chose to review the clinical pathogenicity of these two viruses which were cognate in origin but distinct in virulence. As such, we began with the first of the two above viral diseases and proceeded with peculiar renal involvement, unique clinical symptoms and pertinent lethal risk. Of importance, LN was used to exemplify the reciprocally detrimental interactions between impaired renal function and suppressed immune response. Then in a manner similar to the gradient overlay, SuHV-1 encephalitis was discussed focusing on its neurotropic features, specific MRI findings and exclusive test of high throughput sequencing. Our report highlighted novel presentations of the Varicellovirus genus infection by providing a productive multidisciplinary communication with pointed disclosure of the renal involvement. It may therefore be of great medical relevance and educational value for clinicians, especially the unseasoned ones, to foresee and manage similar cases in susceptible patients.

Nocardiosis in Kidney Disease Patients under Immunosuppressive Therapy: Case Report and Literature Review

The increased use of novel and powerful immunosuppressive drugs in kidney diseases may concomitantly expose the patients to higher risk of opportunistic infections, some of which still remain underdiagnosed thus mishandled. As such, we recently had a less prepared encounter of pulmonary nocardial infection in an ANCA-associated renal vasculitis patient under steroid therapy. Despite the use of broad-spectrum antimicrobials including micafungin, the infection was still unbridled and eventually culminated in lethal brain abscess. We thus chose to renew the knowledge of the clinical features, imaging manifestations, differential diagnosis, specific laboratory tests and unique treatment about this rare infection in kidney diseases patients under immunosuppressive therapy. In addition, CT images of easily confused pulmonary lesions superimposed on kidney diseases were also retrieved from our depository. Moreover, impaired renal function as a risk factor for infection and pharmacological options for the treatment were also focused. By sharing our hard-learnt experience and reviewing the literatures, our report may contribute to the awareness among the clinicians in general and nephrologists in particular of this rare disease in susceptible patients and facilitate a swift thus life-saving treatment.